Between submission and your viva, take an hour or two to see if any recent, relevant papers have been published that you haven’t noticed while you’ve been busy.
You’ve not missed them though. They’re still there. You can read them now.
It could be that one or more of them has something that you could have included in your thesis. But you didn’t. You’ve not missed it. You don’t need it now.
A thesis always has a line drawn under it in some way: I studied and worked up to this point. There’s always more published and always new connections to be made.
But not now. This far. No further.
You check for recent, relevant papers for yourself, to make sure your personal knowledge is more full; you don’t look for more references or new ideas to add to your thesis.
You’ll probably have corrections but those aside your thesis is complete.
